The demand for poultry has expanded considerably over the last decade, particularly in the United States, due to changes in eating habits by the population, resulting in increased consumption of foods which contain less fat and cholesterol. To meet this demand, the poultry industry has had to change from a small home industry to a large scale manufacturing industry. One of the main problems caused by such large scale production is decreased reproductive productivity caused by stressing of the hens which lay the eggs which are allowed to hatch into poultry for consumption. Stress can be caused by overcrowding, moving, handling, changes in environmental conditions, or fright, and is one of the main causes of the decline in productivity, i.e., number of fertile eggs laid and the number of fertile eggs that hatch to yield live chicks. As hens age, they also become less productive.
Thus, there is a need in the art for methods that will allow breeder hens to produce eggs at a high rate for a longer period of their lifetimes. Further there is also a need in the art for methods to alleviate or reverse the deleterious effects of stress on the rate of egg laying by breeder hens as well as on the number of fertile eggs that are laid and that subsequently hatch.
The present inventors have now surprisingly and unexpectedly discovered that it is possible to improve productivity in breeder hens in terms of egg production, number of fertile eggs laid, and rate of hatching by the administration of L-Dihydroxyphenylalanine (hereinafter L-DOPA) to female poultry which lay eggs for hatching, rather than consumption, (i.e., breeder hens) or compositions that increase the concentration of L-DOPA in the bloodstream of breeder hens.
Further, administering L-DOPA or compositions that increase the concentration of L-DOPA in the bloodstream to breeder hens following stress reduces the recovery time needed to achieve the same egg laying productivity rate present before the stress.
In a first aspect, the present invention is directed to a method for increasing egg production by breeder hens by administering an effective amount of L-DOPA, a drug that increases the amount of L-DOPA in the hen""s bloodstream, or a combination thereof to the breeder hens.
In a second aspect, the present invention is directed to a method for increasing the hatch rate of fertile eggs from breeder hens by administering an effective amount of L-DOPA, a drug that increases the amount of L-DOPA in the animal""s bloodstream, or a combination thereof to the breeder hens.
In a third aspect, the present invention is directed to a method for increasing chick production by breeder hens by administering an effective amount of L-DOPA, a drug that increases the amount of L-DOPA in the hen""s bloodstream, or a combination thereof to the breeder hen.
In a fourth aspect, the present invention is directed to a method for increasing the feeding efficiency of chicks hatched from eggs laid by breeder hens by administering an effective amount of L-DOPA, a drug that increases the amount of L-DOPA in the hen""s bloodstream, or a combination thereof to the breeder hens prior to the laying of the eggs from which the chicks hatch.
In yet another aspect, the present invention is directed to a method for reducing the recovery time needed to achieve the same rate of egg laying productivity in breeder hens which have been stressed as before the stress was applied.